[PATCH v3 4/4] mm/page_isolation: remove migratetype parameter from more functions.

Zi Yan
2025-05-07T21:13:03Z

migratetype is no longer overwritten during pageblock isolation,
start_isolate_page_range(), has_unmovable_pages(), and
set_migratetype_isolate() no longer need which migratetype to restore
during isolation failure.

For has_unmoable_pages(), it needs to know if the isolation is for CMA
allocation, so adding CMA_ALLOCATION to isolation flags to provide the
information.

alloc_contig_range() no longer needs migratetype. Replace it with
a newly defined acr_flags_t to tell if an allocation is for CMA. So does
__alloc_contig_migrate_range().

Signed-off-by: Zi Yan <ziy@nvidia.com>
---
drivers/virtio/virtio_mem.c | 3 +--
include/linux/gfp.h | 6 +++++-
include/linux/page-isolation.h | 15 +++++++++++---
include/trace/events/kmem.h | 14 +++++++------
mm/cma.c | 2 +-
mm/memory_hotplug.c | 1 -
mm/page_alloc.c | 22 ++++++++++-----------
mm/page_isolation.c | 36 ++++++++++++----------------------
8 files changed, 50 insertions(+), 49 deletions(-)

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 56d0dbe62163..8accc0f255a8 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -1243,8 +1243,7 @@ static int virtio_mem_fake_offline(struct virtio_mem *vm, unsigned long pfn,
if (atomic_read(&vm->config_changed))
return -EAGAIN;

- rc = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE,
- GFP_KERNEL);
+ rc = alloc_contig_range(pfn, pfn + nr_pages, 0, GFP_KERNEL);
if (rc == -ENOMEM)
/* whoops, out of memory */
return rc;
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index c9fa6309c903..db4be1861736 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -423,9 +423,13 @@ static inline bool gfp_compaction_allowed(gfp_t gfp_mask)
extern gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma);

#ifdef CONFIG_CONTIG_ALLOC
+
+typedef unsigned int __bitwise acr_flags_t;
+#define ACR_CMA ((__force acr_flags_t)BIT(0)) // allocate for CMA
+
/* The below functions must be run on a range from a single zone. */
extern int alloc_contig_range_noprof(unsigned long start, unsigned long end,
- unsigned migratetype, gfp_t gfp_mask);
+ acr_flags_t alloc_flags, gfp_t gfp_mask);
#define alloc_contig_range(...) alloc_hooks(alloc_contig_range_noprof(__VA_ARGS__))

extern struct page *alloc_contig_pages_noprof(unsigned long nr_pages, gfp_t gfp_mask,
diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
index b8b44d3aacd4..709a807202e9 100644
--- a/include/linux/page-isolation.h
+++ b/include/linux/page-isolation.h
@@ -22,8 +22,17 @@ static inline bool is_migrate_isolate(int migratetype)
}
#endif

-#define MEMORY_OFFLINE 0x1
-#define REPORT_FAILURE 0x2
+/*
+ * Isolation flags:
+ * MEMORY_OFFLINE - isolate to offline (!allocate) memory e.g., skip over
+ * PageHWPoison() pages and PageOffline() pages.
+ * REPORT_FAILURE - report details about the failure to isolate the range
+ * CMA_ALLOCATION - isolate for CMA allocations
+ */
+typedef unsigned int __bitwise isol_flags_t;
+#define MEMORY_OFFLINE ((__force isol_flags_t)BIT(0))
+#define REPORT_FAILURE ((__force isol_flags_t)BIT(1))
+#define CMA_ALLOCATION ((__force isol_flags_t)BIT(2))

void set_pageblock_migratetype(struct page *page, int migratetype);

@@ -31,7 +40,7 @@ bool pageblock_isolate_and_move_free_pages(struct zone *zone, struct page *page)
bool pageblock_unisolate_and_move_free_pages(struct zone *zone, struct page *page);

int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
- int migratetype, int flags);
+ isol_flags_t flags);

void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn);

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index f74925a6cf69..efffcf578217 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -304,6 +304,7 @@ TRACE_EVENT(mm_page_alloc_extfrag,
__entry->change_ownership)
);

+#ifdef CONFIG_CONTIG_ALLOC
TRACE_EVENT(mm_alloc_contig_migrate_range_info,

TP_PROTO(unsigned long start,
@@ -311,9 +312,9 @@ TRACE_EVENT(mm_alloc_contig_migrate_range_info,
unsigned long nr_migrated,
unsigned long nr_reclaimed,
unsigned long nr_mapped,
- int migratetype),
+ acr_flags_t alloc_flags),

- TP_ARGS(start, end, nr_migrated, nr_reclaimed, nr_mapped, migratetype),
+ TP_ARGS(start, end, nr_migrated, nr_reclaimed, nr_mapped, alloc_flags),

TP_STRUCT__entry(
__field(unsigned long, start)
@@ -321,7 +322,7 @@ TRACE_EVENT(mm_alloc_contig_migrate_range_info,
__field(unsigned long, nr_migrated)
__field(unsigned long, nr_reclaimed)
__field(unsigned long, nr_mapped)
- __field(int, migratetype)
+ __field(acr_flags_t, alloc_flags)
),

TP_fast_assign(
@@ -330,17 +331,18 @@ TRACE_EVENT(mm_alloc_contig_migrate_range_info,
__entry->nr_migrated = nr_migrated;
__entry->nr_reclaimed = nr_reclaimed;
__entry->nr_mapped = nr_mapped;
- __entry->migratetype = migratetype;
+ __entry->alloc_flags = alloc_flags;
),

- TP_printk("start=0x%lx end=0x%lx migratetype=%d nr_migrated=%lu nr_reclaimed=%lu nr_mapped=%lu",
+ TP_printk("start=0x%lx end=0x%lx alloc_flags=%d nr_migrated=%lu nr_reclaimed=%lu nr_mapped=%lu",
__entry->start,
__entry->end,
- __entry->migratetype,
+ __entry->alloc_flags,
__entry->nr_migrated,
__entry->nr_reclaimed,
__entry->nr_mapped)
);
+#endif

TRACE_EVENT(mm_setup_per_zone_wmarks,

diff --git a/mm/cma.c b/mm/cma.c
index 15632939f20a..8606bfe19e5d 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -818,7 +818,7 @@ static int cma_range_alloc(struct cma *cma, struct cma_memrange *cmr,

pfn = cmr->base_pfn + (bitmap_no << cma->order_per_bit);
mutex_lock(&cma->alloc_mutex);
- ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, gfp);
+ ret = alloc_contig_range(pfn, pfn + count, ACR_CMA, gfp);
mutex_unlock(&cma->alloc_mutex);
if (ret == 0) {
page = pfn_to_page(pfn);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 673d41a06da8..155f0b4ff299 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -2005,7 +2005,6 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages,

/* set above range as isolated */
ret = start_isolate_page_range(start_pfn, end_pfn,
- MIGRATE_MOVABLE,
MEMORY_OFFLINE | REPORT_FAILURE);
if (ret) {
reason = "failure to isolate range";
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b905ed13c908..f2c148a3675a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6581,11 +6581,12 @@ static void alloc_contig_dump_pages(struct list_head *page_list)

/*
* [start, end) must belong to a single zone.
- * @migratetype: using migratetype to filter the type of migration in
+ * @alloc_flags: using acr_flags_t to filter the type of migration in
* trace_mm_alloc_contig_migrate_range_info.
*/
static int __alloc_contig_migrate_range(struct compact_control *cc,
- unsigned long start, unsigned long end, int migratetype)
+ unsigned long start, unsigned long end,
+ acr_flags_t alloc_flags)
{
/* This function is based on compact_zone() from compaction.c. */
unsigned int nr_reclaimed;
@@ -6657,7 +6658,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
putback_movable_pages(&cc->migratepages);
}

- trace_mm_alloc_contig_migrate_range_info(start, end, migratetype,
+ trace_mm_alloc_contig_migrate_range_info(start, end, alloc_flags,
total_migrated,
total_reclaimed,
total_mapped);
@@ -6728,10 +6729,7 @@ static int __alloc_contig_verify_gfp_mask(gfp_t gfp_mask, gfp_t *gfp_cc_mask)
* alloc_contig_range() -- tries to allocate given range of pages
* @start: start PFN to allocate
* @end: one-past-the-last PFN to allocate
- * @migratetype: migratetype of the underlying pageblocks (either
- * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks
- * in range must have the same migratetype and it must
- * be either of the two.
+ * @alloc_flags: allocation information
* @gfp_mask: GFP mask. Node/zone/placement hints are ignored; only some
* action and reclaim modifiers are supported. Reclaim modifiers
* control allocation behavior during compaction/migration/reclaim.
@@ -6748,7 +6746,7 @@ static int __alloc_contig_verify_gfp_mask(gfp_t gfp_mask, gfp_t *gfp_cc_mask)
* need to be freed with free_contig_range().
*/
int alloc_contig_range_noprof(unsigned long start, unsigned long end,
- unsigned migratetype, gfp_t gfp_mask)
+ acr_flags_t alloc_flags, gfp_t gfp_mask)
{
unsigned long outer_start, outer_end;
int ret = 0;
@@ -6790,7 +6788,8 @@ int alloc_contig_range_noprof(unsigned long start, unsigned long end,
* put back to page allocator so that buddy can use them.
*/

- ret = start_isolate_page_range(start, end, migratetype, 0);
+ ret = start_isolate_page_range(start, end,
+ (alloc_flags & ACR_CMA) ? CMA_ALLOCATION : 0);
if (ret)
goto done;

@@ -6806,7 +6805,7 @@ int alloc_contig_range_noprof(unsigned long start, unsigned long end,
* allocated. So, if we fall through be sure to clear ret so that
* -EBUSY is not accidentally used or returned to caller.
*/
- ret = __alloc_contig_migrate_range(&cc, start, end, migratetype);
+ ret = __alloc_contig_migrate_range(&cc, start, end, alloc_flags);
if (ret && ret != -EBUSY)
goto done;

@@ -6898,8 +6897,7 @@ static int __alloc_contig_pages(unsigned long start_pfn,
{
unsigned long end_pfn = start_pfn + nr_pages;

- return alloc_contig_range_noprof(start_pfn, end_pfn, MIGRATE_MOVABLE,
- gfp_mask);
+ return alloc_contig_range_noprof(start_pfn, end_pfn, 0, gfp_mask);
}

static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 1edfef408faf..d1ec98fab6a4 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -31,7 +31,7 @@
*
*/
static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long end_pfn,
- int migratetype, int flags)
+ isol_flags_t flags)
{
struct page *page = pfn_to_page(start_pfn);
struct zone *zone = page_zone(page);
@@ -46,7 +46,7 @@ static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long e
* isolate CMA pageblocks even when they are not movable in fact
* so consider them movable here.
*/
- if (is_migrate_cma(migratetype))
+ if (flags & CMA_ALLOCATION)
return NULL;

return page;
@@ -151,7 +151,7 @@ static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long e
* present in [start_pfn, end_pfn). The pageblock must intersect with
* [start_pfn, end_pfn).
*/
-static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags,
+static int set_migratetype_isolate(struct page *page, isol_flags_t isol_flags,
unsigned long start_pfn, unsigned long end_pfn)
{
struct zone *zone = page_zone(page);
@@ -186,7 +186,7 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
end_pfn);

unmovable = has_unmovable_pages(check_unmovable_start, check_unmovable_end,
- migratetype, isol_flags);
+ isol_flags);
if (!unmovable) {
if (!pageblock_isolate_and_move_free_pages(zone, page)) {
spin_unlock_irqrestore(&zone->lock, flags);
@@ -296,7 +296,6 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
* @isolate_before: isolate the pageblock before the boundary_pfn
* @skip_isolation: the flag to skip the pageblock isolation in second
* isolate_single_pageblock()
- * @migratetype: migrate type to set in error recovery.
*
* Free and in-use pages can be as big as MAX_PAGE_ORDER and contain more than one
* pageblock. When not all pageblocks within a page are isolated at the same
@@ -311,8 +310,8 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
* either. The function handles this by splitting the free page or migrating
* the in-use page then splitting the free page.
*/
-static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
- bool isolate_before, bool skip_isolation, int migratetype)
+static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t flags,
+ bool isolate_before, bool skip_isolation)
{
unsigned long start_pfn;
unsigned long isolate_pageblock;
@@ -338,11 +337,9 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
zone->zone_start_pfn);

if (skip_isolation) {
- int mt __maybe_unused = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
-
- VM_BUG_ON(!is_migrate_isolate(mt));
+ VM_BUG_ON(!get_pageblock_isolate(pfn_to_page(isolate_pageblock)));
} else {
- ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock), migratetype,
+ ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock),
flags, isolate_pageblock, isolate_pageblock + pageblock_nr_pages);

if (ret)
@@ -441,14 +438,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
* start_isolate_page_range() - mark page range MIGRATE_ISOLATE
* @start_pfn: The first PFN of the range to be isolated.
* @end_pfn: The last PFN of the range to be isolated.
- * @migratetype: Migrate type to set in error recovery.
- * @flags: The following flags are allowed (they can be combined in
- * a bit mask)
- * MEMORY_OFFLINE - isolate to offline (!allocate) memory
- * e.g., skip over PageHWPoison() pages
- * and PageOffline() pages.
- * REPORT_FAILURE - report details about the failure to
- * isolate the range
+ * @flags: isolation flags
*
* Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
* the range will never be allocated. Any free pages and pages freed in the
@@ -481,7 +471,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
* Return: 0 on success and -EBUSY if any part of range cannot be isolated.
*/
int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
- int migratetype, int flags)
+ isol_flags_t flags)
{
unsigned long pfn;
struct page *page;
@@ -493,7 +483,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,

/* isolate [isolate_start, isolate_start + pageblock_nr_pages) pageblock */
ret = isolate_single_pageblock(isolate_start, flags, false,
- skip_isolation, migratetype);
+ skip_isolation);
if (ret)
return ret;

@@ -502,7 +492,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,

/* isolate [isolate_end - pageblock_nr_pages, isolate_end) pageblock */
ret = isolate_single_pageblock(isolate_end, flags, true,
- skip_isolation, migratetype);
+ skip_isolation);
if (ret) {
unset_migratetype_isolate(pfn_to_page(isolate_start));
return ret;
@@ -513,7 +503,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
pfn < isolate_end - pageblock_nr_pages;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
- if (page && set_migratetype_isolate(page, migratetype, flags,
+ if (page && set_migratetype_isolate(page, flags,
start_pfn, end_pfn)) {
undo_isolate_page_range(isolate_start, pfn);
unset_migratetype_isolate(
--
2.47.2